The Most Common Causes of Roof Leaks

A home's roof takes a beating during the winter months. Heavy snow, ice build-ups, torrential rains, and high winds not only loosen shingles but also take a heavy toll on other roof components. There are many places a roof can leak. Before the next winter season hits your home, find the leaks and fix them before repairing any interior damage they many have caused.
Three common leak sources are gutters and downspouts, angles on rooftops, and the seals around flashing and vents. Anywhere there's a seam or a hole in the roof surface is a potential site for a leak.
Roofs generally have several peaks and valleys. The biggest one is usually at the very top of the roofline. If your home was built with several attached wings or dormers, there are more opportunities for leaks. Places where two pieces of roofing abut create a perfect opportunity for a leak. These seams are sealed to prevent water infiltration.

Water draining from the roof into gutters and downspouts is normally channeled away from the house to the ground. When gutters and downspouts are clogged by leaves, twigs, and last summer's birds' nests, the water backs up and overflows. A lot of that water cascades over the gutter's edge, splashes against the soffit and fascia under the eaves and runs down the walls. This is a leak looking for a place to happen.
Aluminum flashing and rubber boots prevent water from leaking through holes in the roof where vents, chimneys, and other components enter the house. These sites are sealed with caulking or a rubber gasket-like component to guard against water infiltration. When the caulk or boot deteriorates after exposure to the elements, they are likely to leak.
If you're not sure where your roof is leaking, wait for the next rainstorm and go to your attic. You'll probably find wet spots or dripping water. Follow the water to its highest point. That's usually where the leak is located. If you can't wait for the next storm, wet down the roof with a hose and following the preceding steps.
If you find leaks at roof peaks and valleys, cleaning and resealing the seams is the fastest way to eliminate fewer drips. To be on the safe side, clean the entire roof and reseal it every two years. This isn't cheap and requires some effort but cleaning and resealing is much cheaper than replacing the entire roof or repairing interior water damage.

Clean your gutters and downspouts before winter sets in and again in the spring. Installing screens over the tops of gutters is a one-step solution to clogs. Plastic screens provide a cheap solution but low-maintenance aluminum ones last longer.
Check the rubber boots around vent pipes on a regular basis for deterioration and cracks. Replace the boots if they have stiffened or are starting to crack. Examine the flashing to make sure it is firmly in place and that the caulking is in good condition. Re-nail and re-caulk where necessary.
Flashing and vent boots deteriorate over time because of exposure to the elements. Winter freezing and thawing can enlarge gaps, allowing water to enter. Re-caulking around aluminum flashing and replacing worn vent boots around vent pipes are the usual means of repair.
The bottom line is that consistent, regular maintenance and roof repair is very inexpensive compared to major repairs.